Clean Data & Redesignation Policies

EPA has issued policy memoranda and implementation rules outlining EPA interpretations of the
provisions of the Clean Air Act as they apply to areas that have attained the NAAQS. In designated
nonattainment areas where monitored data demonstrate that the NAAQS have been achieved, EPA
interprets certain requirements of the Clean Air Act as no longer applying for so long as air
quality continues to meet the standard. Therefore, the Agency does not require these areas to submit
to EPA certain SIP elements, including reasonable further progress (RFP) requirements, attainment
demonstrations, reasonable available control measures (RACM), and contingency measures. This
interpretation of the Clean Air Act is known as the Clean Data Policy.

The Clean Data Policy and Regulations

Under EPA's Clean Data Policy and the regulations that embody it,
40 CFR 51.918
(1997 8-hour ozone) and
51.1004(c)
(PM25), an EPA rulemaking determination that an area is attaining the
relevant standard suspends the area's obligations to submit an attainment demonstration, reasonable
available control measures (RACM), reasonable further progress, contingency measures and other
planning requirements related to attainment for as long as the area continues to attain. EPA's
statutory interpretation of the Clean Data Policy is described in the "Final Rule to Implement the
8-hour Ozone National Ambient Air Quality Standard—Phase 2" (Phase 2 Final Rule).
70 FR 71612,
71644-46 (Nov. 29, 2005) (ozone); See also
72 FR 20586,
20665 (Apr. 25, 2007) (PM25). EPA
believes that the legal basis set forth in detail in our Phase 2 Final rule, our
May 10, 1995 memorandum(8 pp, 2,895k)
from John S. Seitz, entitled "Reasonable Further Progress, Attainment Demonstration, and
Related Requirements for Ozone Nonattainment Areas Meeting the Ozone National Ambient Air Quality
Standard," and our
December 14, 2004 memorandum(6 pp, 293k)
from Stephen D. Page entitled "Clean Data Policy for
the Fine Particle National Ambient Air Quality Standards" are equally pertinent to all NAAQS. EPA
has codified the Clean Data Policy for 1997 8-hour ozone and PM25, and has also applied it in
individual rulemakings for 1-hour ozone and PM10.

Under the Clean Data Policy, EPA may issue a determination of attainment (known informally as a
Clean Data Determination) after notice and comment rulemaking determining that a specific area is
attaining the relevant standard. For such areas the requirement to submit to EPA those SIP elements
related to attaining the NAAQS is suspended for so long as the area continues to attain the
standard. These planning elements include reasonable further progress (RFP) requirements, attainment
demonstrations, RACM, contingency measures, and other state planning requirements related to
attainment of the NAAQS. The determination of attainment is not equivalent to a redesignation, and
the state must still meet the statutory requirements for redesignation in order to be redesignated
to attainment. A determination of attainment for purposes of the Clean Data Policy/regulations is
also not linked to any particular attainment deadline, and is not necessarily equivalent to a
determination that an area has attained the standard by its applicable attainment deadline, e.g.,
under section 181(b).

Redesignation Guidance

One principal source of EPA guidance with respect to redesignations to attainment can be found in
a memorandum entitled
"Procedures for Processing Requests to Redesignate Areas to Attainment" (PDF) (13 pp, 812k)
from John Calcagni, Director, Air Quality Management Division, September 4, 1992. It notes, for example, that,
for the purposes of redesignation, a state must meet the applicable requirements of section 110 and
Part D that become due prior to the state's submittal of a complete redesignation request to
EPA. For the purposes of evaluating a redesignation request, the EPA will not need to consider the
required SIP elements that became due after submittal of the redesignation request. However, such
requirements remain due until EPA completes final action approving a redesignation request.

See the EPA Green Book website for comprehensive nonattainment area
information for criteria pollutants. This website includes current area, state and county nonattainment and classification status,
clean data determinations, redesignations, links to associated Federal Register Notices, GIS maps, and
downloadable shapefiles and data exports.